Implement pipeline requirement of github labels

Projects that do not use github reviews may wish to instead use github
labels as a way to trigger pipelines. As such, these projects may also
wish to require labels exist on a pull request when processing other
events.

Change-Id: I8f73c438c58db38790ea7e5bf435fbda01324e77
Story: 2000774
Task: 4632
diff --git a/tests/base.py b/tests/base.py
index 93b5785..4a66de6 100755
--- a/tests/base.py
+++ b/tests/base.py
@@ -936,7 +936,8 @@
                     'full_name': pr.project
                 }
             },
-            'files': pr.files
+            'files': pr.files,
+            'labels': pr.labels
         }
         return data